The paper deals with the distribution of suspended particulated materials (SPM) in the Changjiang Estuary, the relation of salinity to particulated organic carbon and particulated organic nitrogen, and behaviour of SPM in mixing river-sea water.At the same time, the article shows that the SPM in Changjiang River emptying into the sea contains a large amount of organic matter.The relative concentrations of suspended particulate organic matter and living organic matter gradually increase seaward.In the estuarine environment, there is a linear relationship between log SPM and C/N ratio during the mixing of fresh water with seawater.